Secondary Storage

FILE COMPRESSION

File compression is a system that lets Web users reduced the overall number of bits and bytes in a file so that it can be transmitted at a faster speed on a limited broadband. After the file has been downloaded, programs such as WinZip or WinRar can be used to decompress the file back to its original size. The decompressed file is usually identical to the original file, before it was compressed. File compression can also be used to keep multiple files into a single compressed archive to minimize disk space.


HEAD CRASH

A head crash is the hard-disk malfunction that occurs when the read-write head of a hard disk drive, which normally hovers a few microinches from its rotating platter, gets in contact with it, which will result in permanent and usually fatal damage to the magnetic media on the platter surface. It can also happen when dust or debris accumulates on the surface of the platter. If that happens, both the head and the disk will have to be replaced. Also, depending on the severity of the crash, some or all of the data stored on the drive will be lost.


INTERNET HARD DRIVE
Internet hard drives enable the users to backup their files on the Internet through many backup servies available, which means that the files uploaded, such as pictures, documents, music and videos can be accessed from any computer, as long as it is connected to the Internet. With that, backing up files on the Internet may take a long time, as it depends on the speed of the internet. Likewise, uploading your file back on the computer may also take a long time. However, what internet hard drive offers is the freedom to retrieve any document you need from anywhere in the world.


OPTICAL DISK DRIVE

The optical disc drive (ODD) is a disk drive which uses low-powered laser light or electromagnetic waves near the light spectrum to read or write data to or from optical discks. Optical disc drivs are circular, flat, glass or plast disk in which data can be stored in the form of light and dark pits. When the laser beam reads the pits, data can be accessed. They can store up to 6 gigabytes of data, and are a part of stand-alone consumer appliance such as CD and DVD players and recorders. It has mostly replaced magnetic tape drives and floppy disk drives because of the low cost of optical media and the near-ubiquity of optical drives in computers and consumer entertainment hardware.


SOLID-STATE STORAGE

A solid-state storage is a type of nonvolatile, removable data storage device which uses solid-state memory to keep persistent data. It is distinguished from traditional hard disk drives, which are electromechanical devices containing spinning disks and movable read/write heads since solid-state storage does not contains any mechanical parts. Thus, data transfer to and from solid-state storage media takes place at a much higher speed than electromechanical disk drives do. It is also less susceptible to physical shock, quieter, and have lower access time and latency, as it uses integrated circuits rather than magnetic or optical media.

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Input and Output

ERGONOMIC KEYBOARD

First and foremost, ergonomics is the science of designing the workplace environment to provide the most comfort to users. An ergonomic keyboard is designed with considerations to reduce muscle straints on the user's wrists, along with other problems to provide a more comfortable platform for typing. These keyboards are specially designed and contoured so that the wrists will adopt a more natural positions. They are also often recommended by therapists and health care professionals to vigorous computer users.


INK-JET PRINTER

An ink-jet printer is a type of printer that spray small dots of ionized ink into paper precisely to create a specific image. Most ink-jet printers nowadays also include scanner, photocopier, and fax machine to add appeal to consumers. In addition, ink-jet printers less expensive than laser printers. However, they are also considerably slower. Another disadvantage of ink-jet printers is that they need a special type of ink that is known to smudge on inexpensive copier paper.


LASER PRINTER

Laser printer is a type of printer that is known to produce high quality text and images on normal paper within a small amount of time. It uses a non-impact photocopier technology known as xerographic, where the keys do not touch the paper. Instead, a laser beam is utilized to produce an image. The light of the laser changes the electrical charge on the drum wherever it hits. Then, the drum is rolled in toner, which is a dry powdered type of ink, and picked up by the charged parts of the drum. Lastly, the toner is transferred onto a piece of paper and fused to the paper with heat and pressure.


MAGNETIC-INK CHARACTER RECOGNITION (MICR)

MICR, short for Magnetic-Ink Character Recognition, is a character recognition technology, which is font that can be recognized using magnetically charged ink. The technology enables computers which are installed with the right hardware and software to read information off of printed documents. Unlike barcodes, MICR can easily be read by humans. Also, MICR use magnetic printing, characters can be read easily even if they are overprinted or obscured by other marks, such as cancellation stamps. This technology is usually used to print checks, deposit slips, mortgage coupons and many more.


OPTICAL-CHARACTER RECOGNITION (OCR)

OCR, short for Optical-Character Recognition is the electronic translation of scanned images of handwritten, typewritten or printed text into machine-encoded text. It involves photoscanning of the text, analysis of the scanned image and then the translation of the character image into character codes, such as ASCII, which is commonly used in data processing. It is usually used to convert books and documents into electronic files, whether for the record system in an office, or to be published on the internet. This technology has made it possible for materials to be stored using much less storage space than the hard copy materials, and changed the way information is stored, shared and edited.


OPTICAL-MARK RECOGNITION

Optical Mark Recognition (OMR) is a type of technology that can electronically extract intended data from marked fields, such as checkboxes and fill-in fields, on printed forms. It differs from OCR since a recognition engine is not required, which requires the image to have high contrast and an easily-recognizable or irrelevant shape. With the OMR technology, a printed form is scanned to read predefined positions and records where marks are made on the form. It is a useful technology for applications in which large numbers of hand-filled forms need to be processed quickly and with great accuracy, such as surveys, reply cards, questionnaires and ballots.

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The System Unit

FLASH MEMORY

Flash memory, or sometimes called "flash RAM", is a type of EEPROM (Electornically Erasable Programmable Read Only Memory) which is a variation of electically erasable programmable read-only memory, but which, unlike flash memory, is erased and rewritten at the byte level, which is slower than flash memory updating. It is a chip that maintains stored information without requiring a power source. It is a contantly-powered nonvolatile memory that can be erased and reprogrammed in units of memory called blocks. It is often used in portable electronics, like MP3 players, digital cameras and in removable storage devices.


GRAPHIC CARDS

Graphic card is an expansion card whose function is to generate output images to a display. It is the part of the computer that control and enhance how graphics (pictures, videos, programs, animation, 3D) are displayed on your computer screen. Other modern high performance video cards are used for more graphically demanding purposes, such as PC games. The graphic card is a separate component that plugs into a slot on the motherboard, which is the main part of the computer. Though sometimes, the graphic card components are build directly into the motherboard.


SOUND CARDS

A sound card, which is also known as audio card, is an internal computer component that processes audio files in order to provide high-quality playback through computer speakers. A sound plays voice as well as music files, and can handle various audio file formats including .wav, .mp3 and .cda to name but a few. The typical sound has an interface available at the back of the computer with various input and output ports. The quality of the sound card and speakers both affect the overall sound quality of the computer system. Speakers plug directly into the back of the sound card. Many computers have sound capabilities built in, while others require additional expansion cards to provide for audio capability.


NETWORK INTERFACE CARD (NIC)

A network interface card, more commonly referred to as a NIC, is axpansion board that is inserted into a computer which allows computers to be joined together in a LAN, or local area network. Networked computers then communicate with each other using a given protocol or agreed-upon language for transmitting data packets between the different machines, known as nodes. The network interface card acts as the liaison for the machine to both send and receive data on the LAN and provide a dedicated, full-time connection to a network. Most NICs are designed for a particular type of network, protocol, and media, although some can serve mulltiple networks.


PLUG & PLAY

Plug & Play (PnP) is a technology that provides a combination of software and hardware support that enables the Windows operating system to detect and configure hardware with little or no user involvement.  In many earlier computer systems, the user was required to explicitly tell the operating system when a new device had been added. Plug and Play makes it easier to add and configure hardware on a computer. Microsoft made Plug and Play a selling point for its Windows operating systems, but similar capability had long been built into Macintosh computers.


BUS LINE

The bus lines are a collection of communicating eloctronic lines through which data is transmitted in the form of bits. Bus lines connect different parts of the CPU to various other parts, as well as the system board of the computer. The bus lines are like multilane pathway which means that the more bus lines are on the system the greater is the rate of transfer of data along the bus, which means that the computer can run efficiently and will perform the operations at a faster rate.


HDMI

HDMI stands for High Definition Multimedia Interface, which is an uncompressed, all-digital signal, while the aforementioned interfaces are all analog. With an analog interface, a clean digital source is translated into less precise analog, sent to the television, then converted back to a digital signal to display on screen. At each translation, the digital signal loses integrity, resulting in some distortion of picture quality. HDMI preserves the source signal, eliminating analog conversion to deliver the sharpest, richest picture possible. High Definition technology or HD has seen a rapid increase in consumer use especially with HDTVs, HD-DVD and Blu-ray players, HD camcorders and other HD components.


CACHE MEMORY

Cache (pronounced as cash) memory is a special high-speed storage device that is built into a computer's central processing unit (CPU), or located next to it on a separate chip. The CPU uses cache memory to store instructions that are repeatedly required to run programs, improving overall system speed. The advantage of cache memory is that the CPU does not have to use the motherboard's system bus for data transfer. Whenever data must be passed through the system bus, the data transfer speed slows to the motherboard’s capability. The CPU can process data much faster by avoiding the bottleneck created by the system bus.

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